1. Technical Field
The present invention relates to an optical device provided with a vertically aligned liquid crystal panel and a phase compensating element, and a projector incorporating the optical device.
2. Related Art
As past liquid crystal projectors, there have been projectors for forming image light by controlling transmitted light with liquid crystal light valves each provided with a pair of polarization plates disposed in front of and behind a liquid crystal panel. Further, as such a projector, there has been a projector using a negative uniaxial compensating element, for example, for view angle compensation of the vertically aligned (VA) liquid crystal panel (see e.g., JP-A-2006-11298 and U.S. Pat. No. 4,889,412).
However, the compensation principle using the negative uniaxial compensating element for the VA liquid crystal with pretilt requires a space for tilting the element, which causes problems such that fine adjustment after combining the RGB pixels causes pixel misalignment, or that the integration with the liquid crystal panel is not achievable. All of the problems described above are caused by the fact that the negative uniaxial compensating element must be tilted.
In more specific explanations, in the case in which the VA liquid crystal panel is compensated with the negative uniaxial compensating element, it is required in principle to align the pretilt of the liquid crystal with the optical axis of the compensating element with good accuracy. However, since manufacturing variations existing in pretilt of liquid crystal is larger than the required adjustment accuracy, as a result, there arises necessity of tilting the compensating element to fit the pretilt of each of liquid crystal members. As described above, adjustment by tilting the compensating element requires the space for the tilt. Further, even if the adjustment of the tilt of the compensating element is possible, there is caused the pixel misalignment by the thickness of the compensating element in the three LCD projectors after adjusting positions of the pixels of the respective liquid crystal members. Still further, although it is desirable to integrate the compensating element and the liquid crystal panel also from a viewpoint of space saving, if the tilt adjustment is executed individually for each of the liquid crystal panels, the integration can hardly be realized.